Fetal giant neck masses such as cervical teratoma and lymphangioma can grow to such large proportions that the fetal airway becomes distorted and obstructed. In a small number of patients with cervical teratomas, the mass effect pulls the lungs into the apex of the chest and results in pulmonary hypoplasia.
In addition to obstructing the airway, these fetal giant neck masses can compress the esophagus, resulting in polyhydramnios, which can lead to uterine irritability and preterm labor. Unsuspected obstructive fetal giant neck masses often prove fatal because of an inability to secure an airway and ventilate the neonate, which results in hypoxia and acidosis. If the delay is longer than five minutes, anoxic brain injury may occur. This complication is all the more tragic because most of these children have an isolated anomaly and do well after postnatal resection.
A discrepancy between size and dates because of polyhydramnios in fetuses with giant neck masses is a common indication for ultrasonography, leading to prenatal diagnosis. When patients are referred to the Center for Fetal Diagnosis and Treatment with a diagnosis of a fetal neck mass, an in-depth evaluation is performed by our specialized multidisciplinary team. The mother undergoes a level II ultrasound detailing fetal growth and development as well as anatomy, with concentration directed toward the neck mass.
It is important to identify the type of neck mass and its relationship to adjacent structures. A complete obstetric history, physical and genetic evaluation is performed to rule out other problems with the pregnancy. For example, polyhydramnios caused by mass obstruction of the fetal esophagus may lead to preterm labor and may alter the timing of the delivery. An ultra-fast fetal MRI is performed without maternal sedation or fetal paralysis due to new software imaging and has been found to be a useful adjunct to ultrasound and to distinguish the various types of neck masses. A fetal echocardiogram is performed to assess any structural abnormalities of the heart. Parents of a fetuses found to have giant neck masses are immediately counseled regarding treatment options.
If the neck mass is small and does not compromise the airway, close ultrasound surveillance is warranted to follow the growth of the mass. If the fetal giant neck mass grows to obstruct the esophagus causing polyhydramnios, issues with preterm labor must be addressed. For example, the mother may be placed on bedrest, have some of the amniotic fluid removed and in some instances, may receive a medication to decrease amniotic fluid.
Intraoperative photo during the EXIT procedure of a fetus with a large cervical teratoma.
View larger image »If the polyhydramnios persists and the mass continues to grow, the EXIT procedure is the treatment option of choice.
Fetuses diagnosed with a giant neck mass may require the EXIT procedure to provide time to secure an airway while the baby is still attached to the umbilical cord and to preserve uteroplacental gas exchange. The procedure was originally described for delivery of fetuses with diaphragmatic hernia who had undergone in-utero tracheal clip application to induce prenatal lung growth.
We have adapted the EXIT procedure for the management of fetal giant neck mass and have performed more than 60 EXIT procedures to date. The EXIT procedure is not just a Cesarean section. A special uterine stapling device is used to open the uterus to prevent bleeding and general anesthesia is used to preserve uteroplacental blood flow. This allows time to perform procedures such as direct laryngoscopy, bronchoscopy, tracheostomy, surfactant administration, cyst decompression
The same patient nine months after the EXIT procedure and mass resection.
View larger image »and tumor resection, some or all of which may be required to secure the airway and provide adequate ventilation.
There are potential risks to the EXIT procedure. The risk of bleeding from uterine atony is minimized by coordination between the surgeon and anesthesiologist to decrease the concentration of inhalation anesthetic and to administer oxytocin to contract the uterus before cutting the umbilical cord. This technique, in combination with the uterine stapling device, has kept the average intraoperative maternal blood loss at 930 ml, well within the accepted range for traditional Cesarean section. Central to achieving an excellent outcome is the coordination of our experienced team of pediatric surgeons, fetal and maternal anesthesiologists, obstetricians, neonatologists and obstetrical, neonatal and operating room nurses.
What causes fetal giant neck masses? Does it run in families? If we decide to have another baby, is there an increased risk that our next child will also be affected?
Unfortunately, we do not know what causes this disorder. However, we do know that fetal giant neck masses are not a genetic problem and, therefore, does not “run in families.” Your next child faces no greater or lesser risk of developing this problem than any other child.
What risks does this condition pose during pregnancy?
Because giant neck masses compresses the fetal esophagus or "swallowing" tube, the baby is unable to swallow the amniotic fluid that surrounds him or her in the womb. As a result, this fluid builds up to abnormally high levels - a condition known as polyhydramnios.
Why is polyhydramnios a problem?
The excess fluid can bring on preterm labor, resulting in the birth of a baby who is too small to survive or develop normally.
Can polyhydramnios be treated?
Yes, polyhydramnios can be treated. If severe, it can be treated with medication and regular procedures to remove excess fluid from the womb (amniocentesis). To perform the procedure, a local anesthetic is used to numb the skin on the abdomen, and a needle is inserted into the womb to remove some amniotic fluid. During the procedure, ultrasound is used to visualize the fetus, enabling the physician to choose a puncture site that is far away from the baby.
What is an EXIT procedure?
EXIT stands for ex-utero intrapartum treatment. An EXIT procedure is a surgical procedure that is used to deliver babies who have airway compression due to cervical teratomas, cystic hygromas or blockage of the airway such as congenital high airway obstruction (CHAOS). It is similar to a Caesarean section, but there are some important differences.
First, the mother always receives general anesthesia to “put her to sleep” during the surgery. An opening is made in the skin and then in the uterus, similar to a C-section. The baby is then partially delivered through the incision. Anesthesia keeps the uterus soft and relaxed, which allows the placenta to continue to work. While the baby remains attached to the placenta, he or she can receive oxygen and nutrients from mom while the surgeon works to establish an airway that will permit the child to breathe and obtain oxygen independently.
What will happen to my baby after birth? How sick will he or she be? When can the baby come home with us? What kind of care will the baby need?
Some babies need temporary help with breathing and eating. The compression of the windpipe can cause it to become soft, making it prone to collapse. For this reason, a temporary tracheostomy is sometimes necessary to allow the baby to breathe normally until the trachea hardens. A tracheostomy is a surgical opening in the trachea (or “breathing tube”), which makes breathing easier.
In addition, some babies may need to be partially or totally fed using a tube that goes directly into the stomach. While the baby is still in the hospital, parents are trained to administer these tube feedings and to care for the tracheostomy. Home care professionals will also make home visits to monitor the baby's progress and assist with care.
Do you expect babies with this condition to have any short-term problems? What about long-term problems?
During infancy, care focuses on ensuring that the baby can breathe and eat effectively. Long-term problems are not expected. However, children who have had a giant neck mass will receive long-term follow-up care at regular intervals because they are at higher risk for a re-growth of the mass.
Some cervical teratomas arise from the thyroid gland and after the surgery, the baby may need thyroid hormone supplements. Sometimes these supplements are only needed temporarily until the remaining thyroid grows back. The baby's calcium level can also be affected by the cervical teratoma because of its effect on the parathyroid glands. As a result, babies with cervical teratoma occasionally need calcium supplements.
Updated: June 2011